| Summary: | Mestrado em Toxicologia e Ecotoxicologia The present research work has been focused on the importance and complementarity of field and laboratory in vivo and in vitro studies. Fish are often used as bioindicator organisms in biomonitorization studies because they play a major role in the aquatic food-webs. Thus, two representative species of Aveiro Lagoon ichthyofauna were adopted in the present work: the sea bass (Dicentrarchus labrax L.) and the european eel (Anguilla anguilla L.). The field study (Chapter I) concerned the seasonal genotoxic assessment of a polluted lagoon (Ria de Aveiro), using erythrocytic nuclear abnormalaties (ENAs) of D. labrax specimens, collected at six stations of Aveiro lagoon. ENA results demonstrated the existence of a serious risk to fish populations almost at all the sites (except at GAF in spring, RIO in autumn and LAR in winter). Thus, at all the critical sites (BAR, GAF, RIO, LAR and VAG) identified, the results reflected the presence of genotoxic contaminants in the water. In this context, the ENA assay revealed to be a relatively rapid, easy to perform and sensitive genotoxicity test. The laboratory in vivo and in vitro components of the present Master thesis (Chapters II, III, IV and V) was carried out using A. anguilla L. as a biological model. Anguilla anguilla L. was intraperitoneally injected with β-naphthoflavone, (4mg/kg) which is a synthetic flavonoid compound known as a strong hepatic monooxigenases inducer such as ethoxyresourfin-O-deethylase (EROD). A. anguilla L. hepatic microsomes were then isolated and used in EROD activity in vitro studies. The in vitro effects of (i) PAHs - Naphthalene (Naph) and Phenanthrene (Phe); (ii) Resin acid (RAs) – abietic acid (AA) and its derivatives- Retene (Re) on liver microsomal EROD activity were assessed. A consistent dose dependent liver microsomal EROD activity increase in vitro was demonstrated for both Naph and Phe exposure, confirming their strong liver EROD activity in vitro inducer A. anguilla L. (Chapter II). Since ...
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